Time to implement those features isn't currently known. Adding a unit cannon doesn't seem hard as well, yet proven to require significant effort. Also, when saying about things like shields, massfabs or experimentals, what I'm actually assuming is SupCom-style total conversion mod, like RVE for SupCom2. RVE is massive and required ton of work to deliver, and converting PA is even more time-consuming. While it'll be awesome if some modding group have time and interest to take on such a project, probability of such a miracle is quite low.
It takes time for modders to create that stuff. It won't happen overnight. And even then we already have 2 major mods in the works with literal hundreds of smaller mods already. Hek I even made a few smaller mods during development!